EAU 2017: Debate: Small Asymptomatic Stones: Treat Or Observe?

London, England (UroToday.com) Dr. Monga started off his lecture by informing us that from CT colonoscopy study data, we know that about 8% of people may have asymptomatic stones (more prevalent in men than women) with an average stone size of 3mm ranging up to 20mm and an average of 2 stones. When considering that over 20 million abdominal CTs are performed every year in the US that would mean roughly 2 million will have asymptomatic stones. In 7 years follow-up asymptomatic stone patients have a 1 in 2 chance of progressing to surgery.

When we look at data from CIRF after ESWL, we see that 1 in 4 will eventually need surgery again. In patients with asymptomatic stones and recurrent UTI, 48% will have improvement of UTI recurrence after removing urolithiasis, mainly if it concerns E. Coli infections.

So how do we need to treat them? Prophylactic SWL may prevent more invasive surgery in 9% of patients. Patient preference is distributed evenly over SWL/URS and observation.

In summary, Dr. Monga would treat a 4-10 mm asymptomatic stone with favorable Hunfield Units, Skin to Stone Distance and location with SWL and would otherwise observe (smaller or 4-10mm and not as favorable characteristics).

Dr. Miernik debated for observation. The natural history of these stones is not well defined, the risk of progression is unclear and there is no consensus on follow-up or treatment of small asymptomatic renal stones. SWL is not complication free. In the end, this is not a black or white situation, there is only gray. Patient treatment should be individualized and patients should be stratified based on stone size, risk factors and patient preferences.

In the final discussion, Professor Traxer identifies issues every endourologists has encountered such as what to do with multiple small stones and what defines small. He also brings up the fact that not all stones are created equal. Uric acid stones for instance could be treated with chemolysis and infection and cystine stones may need a more active treatment. Multiple small stones may not only need treatment, these patients are also candidates to get a full metabolic workup to identify any underlying causes of urinary stone disease.

Some patients may become symptomatic over time, even if the stone is in the kidney, not causing obstruction or UTI. How do we explain these stones causing any pain? Dr. Monga references the most recent AUA guidelines here and says offering treatment for this issue is reasonable. In that case he would go for URS rather that SWL because of the higher SFR.

Then there remains the question on how to follow these stones and how frequently. Miernik would ultrasound at 6 m and low dose CT at 1y. Further follow up with alternating US and CT is fair. When considering active treatment however a CT is necessary and considered as golden standard.

Debators: Manoj Monga, MD; Professor of Urology, Cleveland Clinic Foundation, Arkadiusz Miernik, MD; Professor of Urology, Freiburg University


1. Sampaio FJ, Zanier JF, Aragao AH, Favorito LA. Intrarenal access: 3-dimensional anatomical study. The Journal of urology 1992;148:1769-73.

Written By: Zhamshid Okhunov, MD, University of California, Irvine

at the #EAU17 - March 24-28, 2017- London, England